Normal Leaf Research Articles

Exogenous N Supply on N Transportation and Reuse during the Rice Grain-Filling Stage and Its Relationship with Leaf Color-Changing Parameters

During the later reproductive period of rice growth, the chlorophyll in the leaves degraded, accompanied by the nitrogen (N) transportation from leaves to panicle, resulting in a change in leaf color from green to yellow. This study aimed to investigate the effects of exogenous N supply on leaf color-changing, N accumulation, N transportation, and N loss of indica-japonica hybrid rice during the grain-filling stage. Two indica-japonica hybrid rice cultivars, Chunyou 167 (CY167) and Chunyou 927 (CY927), which exhibited significant differences in leaf color-changing during the grain-filling stage, were selected as materials for field experiment and hydroponic experiment with low, medium, and high N treatments (LN, MN, and HN). The dynamic changes in SPAD value from heading to maturity were measured and fitted with quadratic function to extract leaf color-changing parameters; labeled 15N was used as N source after heading to trace the source of N in the panicle and the remobilization of vegetative organ N. The results showed that 67.37–72.38% of the panicle N was transported from vegetative organs, the N transport efficiency was the upper three leaves > lower leaves > stem, and about 3.1–35.0% of the transported N was lost via volatilization. The effects of exogenous N concentration on N harvest index, N dry matter/grain production efficiency, N reuse efficiency, and N loss were closely related to leaf color-changing parameters. In MN and HN treatment, the N loss was negatively correlated with the onset time of leaf color-changing (T0) and the final leaf color index (CIf), but positively correlated with the leaf color-changing rate (Rmean). Increasing the supply of exogenous N increased T0 and CIf, but decreased Rmean, N transport/reuse efficiency, N harvest index, and N dry matter/grain production efficiency. Compared to the cultivar CY167 with normal leaf color-changing, the “stay-green” cultivar CY927 had higher T0, CIf, and lower Rmean, resulting in less N volatilization loss, lower N harvest index and N transport efficiency, while higher N reuse efficiency. In conclusion, the exogenous N supply affects leaf color by influencing the transportation and reuse of leaf N during the grain-filling stage.

BnUC1 Is a Key Regulator of Epidermal Wax Biosynthesis and Lipid Transport in Brassica napus.

The bHLH (basic helix-loop-helix) transcription factor AtCFLAP2 regulates epidermal wax accumulation, but the underlying molecular mechanism remains unknown. We obtained BnUC1mut (BnaA05g18250D homologous to AtCFLAP2) from a Brassica napus mutant with up-curling leaves (Bnuc1) and epidermal wax deficiency via map-based cloning. BnUC1mut contains a point mutation (N200S) in the conserved dimerization domain. Overexpressing BnUC1mut in ZS11 (Zhongshuang11) significantly decreased the leaf epidermal wax content, resulting in up-curled and glossy leaves. In contrast, knocking out BnUC1mut in ZS11-NIL (Zhongshuang11-near-isogenic line) restored the normal leaf phenotype (i.e., flat) and significantly increased the leaf epidermal wax content. The point mutation weakens the ability of BnUC1mut to bind to the promoters of VLCFA (very-long-chain fatty acids) synthesis-related genes, including KCS (β-ketoacyl coenzyme synthase) and LACS (long-chain acyl CoA synthetase), as well as lipid transport-related genes, including LTP (non-specific lipid transfer protein). The resulting sharp decrease in the transcription of genes affecting VLCFA biosynthesis and lipid transport disrupts the normal accumulation of leaf epidermal wax. Thus, BnUC1 influences epidermal wax formation by regulating the expression of LTP and genes associated with VLCFA biosynthesis. Our findings provide a foundation for future investigations on the mechanism mediating plant epidermal wax accumulation.

Roles of microbiota in autoimmunity in Arabidopsis leaves

Over the past three decades, researchers have isolated plant mutants that show constitutively activated defence responses in the absence of pathogen infection. These mutants are called autoimmune mutants and are typically dwarf and/or bearing chlorotic/necrotic lesions. Here, from a genetic screen for Arabidopsis genes involved in maintaining a normal leaf microbiota, we identified TIP GROWTH DEFECTIVE 1 (TIP1), which encodes an S-acyltransferase, as a key player in guarding leaves against abnormal microbiota level and composition under high-humidity conditions. The tip1 mutant has several characteristic phenotypes of classical autoimmune mutants, including a dwarf stature, showing lesions, and having a high basal level of defence gene expression. Gnotobiotic experiments revealed that the autoimmune phenotypes of the tip1 mutant are largely dependent on the presence of microbiota as axenic tip1 plants have markedly reduced autoimmune phenotypes. We found that the microbiota dependency of autoimmune phenotypes is shared by several ‘lesion mimic’-type autoimmune mutants in Arabidopsis. It is worth noting that autoimmune phenotypes caused by mutations in two Nucleotide-Binding, Leucine-Rich Repeat (NLR) genes do not require the presence of microbiota and can even be partially alleviated by microbiota. Our results therefore suggest the existence of at least two classes of autoimmunity (microbiota-dependent versus microbiota-independent) in plants. The observed interplay between autoimmunity and microbiota in the lesion mimic class of autoimmunity is reminiscent of the interactions between autoimmunity and dysbiosis in the animal kingdom. These parallels highlight the intricate relationship between host immunity and microbial communities across various biological systems.

Light green leaf sectors of variegated Dracaena fragrans plants show similar rates of oxygenic photosynthesis tо that of normal, dark green leaf sectors

Adaptation and functional significance of chlorophyll deficit in the light green leaf sectors of variegated plants are little known. Efficiency of photosystem II for dark and light adapted states (Fv/Fm and ΔF/Fm’) and fluorescence decrease rates (Rfd) of light green leaf sectors of Dracaena fragrans L. were studied by methods of PAM-fluorometry and video registration. In addition, white light reflectance and transmittance of these leaf sectors were measured using an integrating sphere. Absorption was calculated from reflectance and transmittance. Net CO2 assimilation rates (PN) were measured using a flow chamber and photolytic O2 evolution rates (PAYO2) were studied by a novel method of Fourier photoacoustics which is insensitive to respiration, photorespiration and other processes of O2 uptake. All the photosynthetic parameters (Fv/Fm, ΔF/Fm’, PN and PAYO2) were found to be very close between light green and normal green leaf sectors, whereas chlorophyll content and light absorption were 7.5-fold and 1.47-fold different respectively. Contradiction between low chlorophyll absorption and high (as in normal green sectors) rate of oxygenic photosynthesis in light-green sectors was proposed to be a consequence of different contribution of cyclic electron transport around PSII (CET-PSII) and/or around PSI (CET-PSI) in the total photosynthesis occurring in these sectors. Particularly, it cannot be excluded, that some part of CET activity occurring in normal green leaf sectors may be lost in the light green sectors retaining the same linear (non-cyclic) electron transport (LET) activity as in normal green sectors.

Effects of different growth hormones on Solanum tuberosum L. callus induction and regeneration

This study was carried out to develop a protocol for callus induction, regeneration, shoot, and root induction in two potato cultivars (Riviera and Almonda) that can be further used to develop genetically modified plants. Callus was induced from leaf and internodal explants on Murashige and Skoog's medium (MS) supplemented with different combinations of hormones. The highest percentage of callus induction was obtained from the internodal explants of Riviera cultivar was 100% in Callus Induction Media I (CIM I) supplemented with 2 mg/L Benzyl Adenine (BA), 0.2 mg/L ?-Naphthalene Acetic Acid (NAA), 2 mg/L 2,4-Dichlorophenoxy acetic acid (2,4-D), 0.2 mg/L Kinetin (Kin) and 0.2 mg/L gibberellic acid (GA3). After one-month calli were shifted to Shoot Induction Media I and II (SIM I and SIM II), the highest percentage for shoot induction was 33.3% with the leaf explants of Riviera cultivar on SIM II supplemented with 2 mg/L BA, 0.2 mg/L NAA, 0.5 mg/L Kin and 0.2 mg/L GA3. The root induction percentage was 100% for both cultivars. Regenerated potato plants had normal leaf shapes with uniform morphology. These findings provide valuable insights for developing tissue culture protocols for potato regeneration, which are essential for genetic engineering and potato breeding programs.

Nephroprotective effect of sugarcane (Saccharum officinarum L.) leaves ethanol extract on gentamicin-induced nephrotoxicity in rats.

Kidney damage is commonly attributed to using certain drugs, such as gentamicin, which causes elevated kidney parameters in blood and damage to renal tissue. This damage is often a result of oxidative stress, but it can be mitigated by using antioxidants. Several studies proved the potential of sugarcane (Saccharum officinarum L.) leaves as an antioxidant. Therefore, this experiment aimed to examine the nephroprotective action of sugarcane leaves. Twenty-five Wistar rats were separated into the normal, negative, and sugarcane leaf extract (SLE) (200, 400, and 600 mg/kg BW) groups. The animals were handled for 8 days, and then, the blood and tissue were collected 24 h later. The results revealed that SLE prevents increased creatinine, blood urea nitrogen, uric acid, and malondialdehyde levels. The histology analysis indicated that the extract improved kidney morphology and histopathology. Sugarcane leaves have the potential to be a nephroprotective agent.

Characteristics, Relationships, and Anatomical Basis of Leaf Hydraulic Traits and Economic Traits in Temperate Desert Shrub Species.

Shrubs are a key component of desert ecosystems, playing a crucial role in controlling desertification and promoting revegetation, yet their growth is often impeded by drought. Leaf hydraulic traits and economic traits are both involved in the process of water exchange for carbon dioxide. Exploring the characteristics, relationships, and anatomical basis of these two suites of traits is crucial to understanding the mechanism of desert shrubs adapting to the desert arid environment. However, the relationship between these two sets of traits currently remains ambiguous. This study explored the leaf hydraulic, economic, and anatomical traits of 19 desert shrub species. The key findings include the following: Relatively larger LT values and smaller SLA values were observed in desert shrubs, aligning with the "slow strategy" in the leaf economics spectrum. The relatively high P50leaf, low HSMleaf, negative TLPleaf, and positive HSMtlp values indicated that severe embolism occurs in the leaves during the dry season, while most species were able to maintain normal leaf expansion. This implies a "tolerance" leaf hydraulic strategy in response to arid stress. No significant relationship was observed between P50leaf and Kmax, indicating the absence of a trade-off between hydraulic efficiency and embolism resistance. Certain coupling relationships were observed between leaf hydraulic traits and economic traits, both of which were closely tied to anatomical structures. Out of all of the leaf traits, LT was the central trait of the leaf traits network. The positive correlation between C content and WPleaf and HSMleaf, as well as the positive correlation between N content and HSMtlp, suggested that the cost of leaf construction was synergistic with hydraulic safety. The negative correlation between SLA, P content, GCL, and SAI suggested a functional synergistic relationship between water use efficiency and gas exchange rate. In summary, this research revealed that the coupling relationship between leaf hydraulic traits and economic traits was one of the important physiological and ecological mechanisms of desert shrubs for adapting to desert habitats.

Maize leaf disease image enhancement algorithm using TFEGAN

Maize leaf diseases have a profound impact on maize crop yield. However, due to practical constraints, gathering a substantial number of maize disease images is time-consuming and labor-intensive. Furthermore, low-light conditions and noise interference in maize leaf disease images present significant challenges for image generation. Therefore, this paper proposes TFEGAN, a novel algorithm designed to generate maize leaf disease images. TFEGAN leverages a Two-Way Extraction Module (TWEM) to enhance the perceptual domain of the model and effectively reuse maize leaf disease features. The algorithm employs two well-trained Generative Adversarial Networks (GANs) to enhance low-light and noisy maize leaf disease images. The low-light enhancement component utilizes a double discriminator and self-regularization to balance global and local enhancement while constraining the distance between the input image and the denoising component. Moreover, the denoising part employs a strong coordinated attention mechanism and an environmental encoder to learn noise regions and their surrounding structures, thus generating better local images and enabling more accurate evaluation by the discriminant network. The generators of both networks are encapsulated by two discriminators and combined with a bi-directional feature extraction structure to generate normal maize leaf disease images. Experimental evaluations demonstrate the effectiveness of TFEGAN in improving the quality of maize leaf disease images under low-light and noisy conditions, showcasing its potential for practical applications. Overall, this paper presents a promising solution to the challenges of low-light and noise interference in maize leaf disease images, utilizing bidirectional feature extraction and GANs.

Analysis of inheritance in a novel seedling stage zebra leaf mutant, Pusa Zebra 18 in rice (Oryza sativa L.)

A novel zebra leaf mutant, Pusa Zebra 18 derived spontaneously from F2 intercross population of Pusa 44 near-isogenic lines (NILs) exhibits distinguishable yellowish cross bands across the green leaf blade, specifically expressed in the seedling stage from 6 DAT, which diffuses progressively, leading to the recovery of the normal green leaf by 30 DAT. We elucidated the genetics and nature of inheritance for zebra trait in F2 and BC1F2 populations by crossing Pusa 6B with Pusa Zebra 18. The leaves of the F1 were a normal green color, indicating that the seedling stage zebra leaf trait in Pusa Zebra 18 is recessive. Chi-square goodness of fit analysis of these segregating populations showed that the segregation ratio was fitting to the Mendelian segregation ratio of 3:1. The seedling stage zebra leaf mutation in Pusa Zebra 18 is monogenic recessive in nature. Further, mapping, fine mapping, cloning, and functional characterization need to be carried out, which will help gain insight into the mechanism involved in chlorophyll biosynthesis and regulation studies in rice.

Morphological Analyses and QTL Mapping of Mottled Leaf in Zucchini (Cucurbita pepo L.).

The mottled leaf is one of the agronomic traits of zucchini and can be applied as a marker trait in aggregation breeding. However, the genetic mechanism responsible for mottled leaf has yet to be elucidated. In the present study, we used two inbred lines (line '19': silver mottled leaf; line '113': normal leaf) as parents for the physiological and genetic analysis of mottled leaf. The synthesis and net photosynthetic rate of chlorophyll were not significantly affected in the mottled areas of leaves. However, we detected a large space between the palisade parenchyma in the leaf mottle area of line '19', which may have caused the mottled leaf phenotype. Light also plays an important role in the formation of mottled leaf, and receiving light during the early stages of leaf development is a necessary factor. Genetic analysis has previously demonstrated that mottled leaf is a quantitative trait that is controlled by multiple genes. Based on the strategy of quantitative trait locus sequencing (QTL-seq), two QTLs were identified on chromosomes 1 and 17, named CpML1.1 and CpML17.1, respectively. Two major loci were identified using R/qtl software version 1.66 under greenhouse conditions in April 2019 (2019A) and April 2020 (2020A) and under open cultivation conditions in May 2020 (2020M). The major QTL, CpML1.1, was located in a 925.2-kb interval on chromosome 1 and explained 10.51%-24.15% of the phenotypic variation. The CpML17.1 was located in a 719.7-kb interval on chromosome 17 and explained 16.25%-38.68% of the phenotypic variation. Based on gene annotation, gene sequence alignment, and qRT-PCR analysis, the Cp4.1LG01g23790 at the CpML1.1 locus encoding a protein of the TPX2 family (target protein of Xklp2) may be a candidate gene for mottled leaf in zucchini. Our findings may provide a theoretical basis for the formation of mottled leaf and provide a foundation for the fine mapping of genes associated with mottled leaf. Molecular markers closely linked to mottled leaf can be used in molecular-assisted selection for the zucchini mottled leaf breeding.

Molecular and metabolic insights into purplish leaf coloration through the investigation of two mulberry (Morus alba) genotypes

BackgroundLeaf coloration in plants, attributed to anthocyanin compounds, plays a crucial role in various physiological functions, and also for pharmaceutical and horticultural uses. However, the molecular mechanisms governing leaf coloration and the physiological significance of anthocyanins in leaves remain poorly understood.ResultsIn this study, we investigated leaf color variation in two closely related mulberry genotypes, one with purplish-red young leaves (EP) and another with normal leaf color (EW). We integrated transcriptomic and metabolomic approaches to gain insights into the metabolic and genetic basis of purplish-red leaf development in mulberry. Our results revealed that flavonoid biosynthesis, particularly the accumulation of delphinidin-3-O-glucoside, is a key determinant of leaf color. Additionally, the up-regulation of CHS genes and transcription factors, including MYB family members, likely contributes to the increased flavonoid content in purplish-red leaves.ConclusionThese findings enhance our understanding of the molecular mechanisms responsible for the purplish coloration observed in mulberry leaves and also offer supporting evidence for the hypothesis that anthocyanins serve a protective function in plant tissues until the processes of light absorption and carbon fixation reach maturity, thereby ensuring a balanced equilibrium between energy capture and utilization.

Aphids increase their rate of survival on emergent aquatic plants through niche construction.

Flooding or rain is a threat to many insects in nature, including herbivorous invertebrates whose hosts are emergent aquatic plants. They may thus have developed particular adaptations to withstand the flooding that is a feature of emergent plants' environment. The aphid Hyalopterus pruni (Hemiptera: Aphididae) modifies the physical and chemical conditions of its habitat by periodically spreading wax around itself with its hind legs. This behaviour constitutes a form of niche construction. We hypothesized that the aphid decreases its risk of death of own or around other individuals when submerged in water by spreading wax powder secreted from its body onto the leaves of its host plant, Phragmites australis. We compared the hydrophobicity of waxed and normal leaf surfaces. Next, we compared the survival rates of wax-powdering and nonwax-powdering aphids under submerged and rainy conditions in the laboratory and in the field. Finally, we examined whether the aphids' wax-powdering behaviour increased as a result of experiencing brief submergence or rain. The surface of the waxed area was significantly more water-repellent than the surface of unwaxed leaves. The waxed areas held air bubbles when under water. In experiments, aphids without wax around themselves exhibited lower survival rates: 22.9% in laboratory conditions and 15.7% in field conditions after 48 hr underwater. In contrast, aphids that secreted wax had higher survival rates, with 41.5% and 38.2% under laboratory and field conditions, respectively, after the same duration. Aphids exposed to rainfall showed similar results. Moreover, aphids that had experienced rain or submersion for 24 hr engaged in increased wax-powdering behaviour. These results indicate that aphids reduce their risk of drowning by powdering secreted wax onto the surface of leaves around them. Our findings suggest that niche construction by herbivorous invertebrates supports their ability to utilize host plants that grow under stressful conditions, such as emergent plants that are subject to periodic inundation.

Sub-okra leaf shape conferred via chromosomal introgression from Gossypium barbadense L. improves photosynthetic productivity in short-season cotton (Gossypium hirsutum L.).

Leaf shape is a vital agronomic trait that affects plant and canopy architecture, yield, and other production attributes of upland cotton. Compared with normal leaves, lobed leaves have potential advantages in improving canopy structure and increasing cotton yield. A chromosomal introgression segment from Gossypium barbadense L. conferring sub-okra leaf shape to Gossypium hirsutum L. was identified on chromosome D01. To determine the effects of this transferred sub-okra leaf shape on the leaf anatomical characteristics, photosynthesis-related traits, and yield of short-season cotton, we performed a field experiment with three sets of near-isogenic lines carrying okra, sub-okra, and normal leaf shape in Lu54 (L54) and Shizao 2 (SZ2) backgrounds. Compared with normal leaves, sub-okra leaves exhibited reduced leaf thickness and smaller leaf mass per area; moreover, the deeper lobes of sub-okra leaves improved the plant canopy structure by decreasing leaf area index by 11.24%-22.84%. Similarly, the intercepted PAR rate of lines with sub-okra leaf shape was also reduced. The chlorophyll content of sub-okra leaves was lower than that of okra and normal leaf shapes; however, the net photosynthetic rate of sub-okra leaves was 8.17%-29.81% higher than that of other leaf shapes at most growth stages. Although the biomass of lines with sub-okra leaf shape was less than that of lines with normal leaves, the average first harvest yield and total yield of lines with the sub-okra leaf shape increased by 6.36% and 5.72%, respectively, compared with those with normal leaves. Thus, improvements in the canopy structure and photosynthetic and physiological characteristics contributed to optimizing the light environment, thereby increasing the yield of lines with sub-okra leaf shape. Our results suggest that the sub-okra leaf trait from G. barbadense L. may have practical applications for cultivating short-season varieties with high photosynthetic efficiency, and improving yield, which will be advantageous for short-season varieties.

Early Disease Detection in Plants using CNN

The Indian economy benefits from early disease detection in plant leaves. According to reports, 10-30% of crops suffer harm from diseases that are not discovered during the curing process. Recent advancements in deep learning, particularly Convolutional Neural Networks (CNNs), have paved the way for transformative solutions in disease identification for agriculture. This study addresses the critical issue of early disease detection by harnessing the power of deep learning models, specifically CNNs. Different leaf disease detection technologies are used for different crops. The pre-trained deep learning model is used in this study to identify and categorize leaf diseases. A dataset of tomato, potato, and bell pepper leaf pictures from the plant village repository was employed for the current investigation. The developed model can detect 12 plant diseases in normal leaf tissue. The quantitative assessment of our CNN-based technique reveals an impressive accuracy rate of 86.21%. This notable accuracy underscores the efficacy of our approach in the challenging domain of plant disease detection. Our findings show potential for the larger agricultural environment beyond the immediate quantitative advantages. This technical advance not only paves the way for improved crop output and lower losses, but also brings in a new era of data-driven sustainability in agriculture. The bottom line is that our research "offers a tangible pathway for leveraging AI-powered solutions to address the long-standing challenges of plant disease detection, thereby significantly contributing to the well-being of farmers and the sustenance of the Indian agricultural sector.

Vitis vinifera L. variety Syrah sprayed with ZnSO4: Effect on fruit quality and winemaking

In grapevines, Zn is essential for normal leaf growth, shoot elongation and pollen development, allowing a fully developed berry. In this context, using as a test system Vitis vinifera L. variety Syrah, this study aimed to assess the interactions between Zn enrichment in grapes and sugars and fatty acids profiles, further considering the sensory implications of red wine production. Vineyard conditions of the soil were assessed to ensure the natural optimal development of grapevines and the workflow for Zn enrichment considered three treatments: foliar spray with water (control) and with ZnSO4 (at 450 and 900g.ha-1). After the 2nd foliar application of ZnSO4, only minor changes of Zn, Ca and P contents were found in grapes (the levels of K, Cu and S increased significantly with ZnSO4 (450 g.ha-1). At harvest, the grapes submitted to foliar application of ZnSO4 showed significantly higher levels of Zn (between 33.38 - 54.41%), but significant deviations in sugars (sucrose, glucose and fructose), fatty acids (C18:0, C18:1, C18:2, C18:3, C16:0, C<16:0) and color parameters were not found. After winemaking, relative to the control, a higher content of Zn persisted (60.59 - 63.82%), without impairing the characteristics desired by consumers. In fact, the wine with ZnSO4 (900 g.ha-1) was the most sensorially accepted.
 Keywords: Foliar spraying with ZnSO4; Grapes enrichment with Zn; Nutrient’s interactions; Sugars and fatty acids profiles; Vitis vinifera L. variety Syrah; Winemaking.

Discovering Nature's shield: Metabolomic insights into green zinc oxide nanoparticles Safeguarding Brassica parachinensis L. from cadmium stress

Heavy metal cadmium (Cd) hinders plants' growth and productivity by causing different morphological and physiological changes. Nanoparticles (NPs) are promising for raising plant yield and reducing Cd toxicity. Nonetheless, the fundamental mechanism of nanoparticle-interfered Cd toxicity in Brassica parachineses L. remains unknown. A novel ZnO nanoparticle (ZnO-NPs) was synthesized using a microalgae strain (Chlorella pyrenoidosa) through a green process and characterized by different standard parameters through TEM, EDX, and XRD. This study examines the effect of different concentrations of ZnO-NPs (50 and 100 mgL−1) in B. parachineses L. under Cd stress through ultra-high-performance liquid chromatography/high-resolution mass spectrometry-based untargeted metabolomics profiling. In the presence of Cd toxicity, foliar spraying with ZnO-NPs raised Cu, Fe, Zn, and Mg levels in the roots and/or leaves, improved seedling development, as demonstrated by increased plant height, root length, and shoot and root fresh weight. Furthermore, the ZnO-NPs significantly enhanced the photosynthetic pigments and changed the antioxidant activities of the Cd-treated plants. Based on a metabolomics analysis, 481 untargeted metabolites were accumulated in leaves under normal and Cd-stressed conditions. These metabolites were highly enriched in producing organic acids, amino acids, glycosides, flavonoids, nucleic acids, and vitamin biosynthesis. Surprisingly, ZnO-NPs restored approximately 60% of Cd stress metabolites to normal leaf levels. Our findings suggest that green synthesized ZnO-NPs can balance ions’ absorption, modulate the antioxidant activities, and restore more metabolites associated with plant growth to their normal levels under Cd stress. It can be applied as a plant growth regulator to alleviate heavy metal toxicity and improve crop yield in heavy metal-contaminated regions.

Effect of Different Biochemical Parameters and Antioxidant Enzymes Activities on Drought Indices in Chickpea (Cicer arietinum L.)

Background: Drought is the foremost environmental restraint that effects the growth and yield of chickpea. The mechanism of response to drought differs with genotype and growth stages of individual crop species. The activation of antioxidant enzymes is an alternate defensive system against oxidative stress that ultimately decide development of putative drought tolerant mechanism. Methods: Eighty-three chickpea genotypes were grown under normal and drought stress conditions and leaf samples were used to estimate different biochemical parameters including total sugar, lipid peroxidation (MDA), chlorophyll, proline and protein along with estimation of activities of different antioxidant enzymes viz., catalase (CAT) (EC 1.11.1.6), ascorbate peroxidase (APX) (EC 1.11.1.11), superoxide dismutase (SOD) and peroxidase (POX). Result: Positively significant correlation was found among proline under control with proline underwent stress (r=0.441), MDA under stress with proline under control (r=0.365) and MDA under control (r=0.336) at 1% level of significance. Positively significant correlation was also investigated between SOD under stressed condition with SOD under control (r=0.665), POX (0.449) and APX under stress (0.423), CAT under control (0.471) and CAT under stress condition (0.374) at 1% probability level. Heatmaps along with dendrograms represented expression levels of different antioxidant enzymes activities that showed variations among different genotypes. In conclusion. total sugar, proline and Malondialdehyde, have been increased under drought stressed condition whilst total chlorophyll and protein were decreased. While antioxidant enzymes viz., POX, APX, CAT and SOD levels increased under drought stressed conditions.

The trait co-variation regulates the response of bryophytes to nitrogen deposition: A meta-analysis

The nitrogen deposition has the potential to alter the trait composition of plant communities by affecting the fitness and physiological adaptation of species, consequently exerting an influence on ecosystem processes. Despite the importance of bryophytes in nutrient and carbon dynamics across different ecosystems, there is a lack of research examining the relationship between nitrogen deposition and the co-variation of bryophyte traits. To address this gap, a meta-analysis was conducted using data from 27 independent studies to investigate potential associations between trait co-variation of bryophytes and nitrogen deposition. The results revealed that interspecific variability regulates the influence of nitrogen deposition on bryophytes by affecting trait co-variation. Multiple correspondence analysis identified six combinations of closely related traits. For example, species with unbranched main stems frequently exhibit robust leaf midribs, leading to leaf wrinkling and leaf clasping around the stem as a response to water loss. Some weft or mat species tend to obtain resources (nitrogen) through their scale hairs on the main stem. Some species with narrow leaves require leaf teeth to maintain a normal leaf shape. The subgroup analyses indicated that certain traits, including unbranched main stem, changes in leaf morphology, robust leaf midrib, main stem without scale hairs, narrow leaf, leaf margin with teeth, undeveloped apophysis, and erect capsule minimize interaction with pollutants and represent a resource strategy. Conversely, functional traits representing a resource acquisition strategy, such as branched main stem, no changes in leaf morphology, short and weak leaf midrib, main stem with scale hairs, broad leaf, leaf margin without teeth, developed apophysis, and non-erect capsule increase pollutant exposure. Overall, our results suggest that anthropogenic global change may significantly impact bryophytes due to changes in their individual physiology and colony ecological indicators caused by increased nitrogen deposition.

Ardisiarecurvipetala (Primulaceae-Myrsinoideae), a new species from northern Peninsular Malaysia.

Recent fieldwork in Terengganu, Peninsular Malaysia, resulted in the collection of an endemic new species of Ardisia, described here as Ardisiarecurvipetala Julius, Siti-Munirah & Utteridge. The species is a member of subgenus (§) Crispardisia on account of its vascularised glands (bacterial nodules) on the leaf margin and the terminal inflorescence on a specialised lateral branch subtended by a normal leaf (rather than a reduced bract-like leaf). Ardisiarecurvipetala is unique amongst all members of §Crispardisia by having leaf margins with both vascularised glands and pustule-like structures and can be further distinguished from other Peninsular Malaysian members of this subgenus by the lamina raised between the leaf venation giving a somewhat bullate appearance, unbranched inflorescences, brownish-red pedicels and recurved corolla lobes, each with a creamy-white apex and a small pink patch at the base. Ardisiarecurvipetala is known only from a single location in Terengganu and its conservation status is assessed as Data Deficient (DD).

Mapping and Functional Analysis of LE Gene in a Lethal Etiolated Rice Mutant at Seedling Stage

An EMS-induced mutant le (lethal etiolated) obtained from a rice variety Zhongjian 100, was characterized by lethal etiolated phenotypes with significantly lower contents of chlorophyll a, chlorophyll b, total chlorophyll and carotenoids, as well as significantly decreased the number of chloroplast grana and irregular and less-stacked grana lamella. The root length, root surface area and root volume of le plants were markedly reduced relative to the wild type. The mutant le showed significantly lower catalase activity and total protein content, significantly higher peroxidase activity,. Using the map-based cloning method, LE gene was mapped to an interval of 48 kb between markers RM16107 and RM16110 on rice chromosome 3. A mutation (from T to C) at the nucleotide position 692 bp of LOC_Os03g59640 (ChlD) occurred, resulting in a change from leucine to proline. By crossing HM133 (a pale green mutant with a single-base substitution of A for G on the exon 10 of ChlD subunit) with a heterozygous line of le (LEle), two plant lines heterozygous at the LE locus and HM133 locus were obtained. Among 15 transgenic plants, 3 complementation lines displayed normal leaf color with significant higher total chlorophyll and chlorophyll a and b contents. The ChlD subunit of the mutant was unable to interact with the ChlI subunit, as demonstrated by a yeast two-hybrid assay. The mutation in le led to lethal etiolated phenotype, but no such phenomenon was observed in the mutants. The interaction between the ChlD and ChlI subunits, chlorophyll synthesis, and chloroplast development may all be impacted by the mutation, which could ultimately result in plant death. The mutation in the AAA+ domain of ChlD blocked the interaction of ChlDle with ChlI, leading to the loss of function of ChlD and hindering chlorophyll synthesis and chloroplast development, and ultimately causing lethal etiolated phenotype of the mutant.